Abstract. Maknoi C, Saensouk S, Saensouk P, Rakarcha S, Thammarong W. 2021. Two new species of Curcuma L. (Zingiberaceae) from Thailand. Biodiversitas 22: 3910-3921. Curcuma aruna and C. pitukii, two new species from northern Thailand, are described, illustrated, and photographed. They are endemic to Sukhothai and Lampang Provinces, northern Thailand, and the morphological characteristics of two new species are compared with their closest species, C. flaviflora, C. eburnea, and C. pierreana. Two new species, C. aruna and C. pitukii are assignable to Curcuma subgenus Ecomata. C. aruna is recognized by leaves ovate with thin chartaceous, fertile bracts 6–12, it’s glabrous on nearly all parts of the plant, flowers yellow and labellum yellow with 2 darker yellow bands in the center. C. pitukii is recognized by bracts 20–40 with purplish white to purple, corolla lobes purplish white to pale purple, staminodes white, and labellum white with an embossed yellow path along the midrib from base to apex. A detailed description, distribution, ecology, etymology, preliminary conservation status, and photographs of two new species are provided. A key to 20 species of Curcuma subgenus Ecomata in Thailand is presented.

It is a family of small to large trees, shrubs or rarely herbs with 22 genera and 325 species (Prance, 2012), distributed mainly in the moist lowland Neotropics, tropical west and east Africa and tropical Asia to north Australia (Prance & Mori, 2004). Ecologically, many species are found in swampy forest areas, montane evergreen and mixed deciduous forests, while a few species occur in open areas. They can be found from sea level to 3,500 m in altitude (Thammarong, 2017). The family is characterised by alternate simple leaves, racemose or paniculate inflorescences or solitary flowers that are hermaphroditic, actinomorphic or zygomorphic with numerous stamens connate at

A new species of Barringtonia (Lecythidaceae), B. thailandica, is described from eastern Thailand. This species resembles B. acutangula in habit, leaf and flower characters, but differs mainly by its ellipsoid-shaped fruit with eight ribs. Additionally, B. schmidtii is reinstated as an independent species and it can be distinguished from its closely related taxa B. acutangula by its swollen leaf base, tomentose rachis, hypanthium and sepals, yellow filaments as well as obovoid-shaped, 4-angled and puberulent fruit. B. bicolor and B. badia are conspecific with B. schmidtii.

The monotypic genus Dimetra, represented by D. craibiana, was previously known to be endemic to Thailand. A specimen from Xaignabouri Province, Lao PDR is reported here as new generic record for Lao PDR; a detailed description and photographs are provided.

Stemona fimbritepala (Stemonaceae), a new species from northern Laos, is described and illustrated. It is morphologically similar to S. hirtella and S. kerrii but clearly differs in longer peduncle, longer tepals, longer petaloid outgrowth of the connective and fimbriate margin of inner tepals. A detailed description, distribution, ecology, etymology, preliminary conservation status and photographs of this species are provided. A key to discriminate between the three hairy species is presented.